Optimization of Process Parameters in Drilling of Hybrid Aluminium Matrix Composites

Abstract

ABSTRACT newlineMetal Matrix Composites (MMCs) are a class of materials that newlineconsists of metal alloys reinforced with a variety of materials. MMCs newlinefind wide applications due to enhanced mechanical properties and their newlineability to effectively function at a higher temperature unlike polymer newlinematrix composites. Aluminium and its alloys are the most popular newlinematrix material used in MMCs. Aluminium matrix composites (AMCs) newlineare a class of advanced materials which have been developed for newlineweight-critical applications. Particle reinforced AMCs are increasingly newlineused in various automobile and aerospace applications since, they newlineexhibit isotropic properties. In addition, they can be fabricated using newlineconventional methods. Aluminium Silicon (Al-Si) alloys and AMCs newlineare used in the manufacturing of various automotive engine components, newlinesuch as cylinder blocks, pistons and piston ring inserts. newlineIn this study Al-Si alloy (LM6) was used as the matrix newlinematerials for fabrication of AMCs and hybrid AMCs by stir casting newlinemethod. AMCs containing 3%, 6% and 9% boron carbide of average newlineparticle size 63 µm and 3%, 6% and 9% fly ash of average particle size newline12 µm were fabricated. Hybrid AMCs containing 1.5%, 3% and 4.5% newlineboron carbide and 1.5%, 3% and 4.5% fly ash were also fabricated. newlineOptical micrographs of the composites were taken and the reinforcement newlineparticles were uniformly distributed in the matrix. newlinev newlineThis research work attempts to develop an appropriate newlinemachining strategy for drilling of AMCs. The four important process newlineparameters such as feed rate, spindle speed, drill material and percentage newlinereinforcement are taken as input parameters; thrust force, surface newlineroughness and burr height are the measures of process performance. The newlineexperiments have been carried out using the Taguchi s orthogonal array newlineand analyzed using signal to noise ratio analysis and grey relational newlineanalysis for finding the single objective and multi objective optimum newlineprocess parameters respectively. Analysis of variance (ANOVA) has newlinebeen used to find the percentage contribution of the parameters and that newlineof their interactions. newlineThe S/N ratio analysis results show that the feed rate is the newlinemost significant parameter for obtaining low thrust force, surface newlineroughness and burr height values. Grey relational analysis (GRA) is newlineused for finding the optimum parameters to achieve low thrust force, newlinesurface roughness and burr height values simultaneously. Drill material newlineis having highest influence in B4C reinforced Composites. Feed rate is newlinehaving highest influence on Fly Ash reinforced Composites. Feed rate newlineand Spindle Speed is having highest influence for Hybrid Composites newlinefor obtaining the optimum process parameters. newlineThe present study suggests that by using correct amount of newlinereinforcement particles, it is possible to obtain tailor made composites newlinefor a particular application. The present work provides useful insight to newlineindustrial composite manufacturers especially for automotive industries. newline